package com.cr4y0n.hot100;

import java.util.ArrayList;
import java.util.List;

/**
 * @author cr4y0n
 * <a href="https://leetcode.cn/problems/spiral-matrix/description/?envType=study-plan-v2&envId=top-100-liked">螺旋矩阵</a>
 * 给你一个 m 行 n 列的矩阵 matrix ，请按照 顺时针螺旋顺序 ，返回矩阵中的所有元素。
 * 示例 1：
 * 输入：matrix = [[1,2,3],[4,5,6],[7,8,9]]
 * 输出：[1,2,3,6,9,8,7,4,5]
 * 示例 2：
 * 输入：matrix = [[1,2,3,4],[5,6,7,8],[9,10,11,12]]
 * 输出：[1,2,3,4,8,12,11,10,9,5,6,7]
 */
public class _54_SpiralMatrix {
    static class Solution {
        public List<Integer> spiralOrder(int[][] matrix) {
            int top = 0;
            int bottom = matrix.length - 1;
            int left = 0;
            int right = matrix[0].length - 1;
            ArrayList<Integer> list = new ArrayList<>();
            while (top <= bottom && left <= right) {
                for (int i = left; i <= right; i++) {
                    list.add(matrix[top][i]);
                }
                top++;
                for (int i = top; i <= bottom; i++) {
                    list.add(matrix[i][right]);
                }
                right--;
                if (top <= bottom) {
                    for (int i = right; i >= left; i--) {
                        list.add(matrix[bottom][i]);
                    }
                    bottom--;
                }
                if (left <= right) {
                    for (int i = bottom; i >= top; i--) {
                        list.add(matrix[i][left]);
                    }
                    left++;
                }
            }
            return list;
        }
    }
}
